Nabi's doa for debt is: 'Allahumma ikfini bi halalika 'an haramik, wa aghnini bi fadlika 'amman siwak' — O Allah, suffice me with what is lawful against what is unlawful, and make me independent of all others besides You. He also taught a doa that could pay off a mountain of debt.
اللَّهُمَّ اكْفِنِي بِحَلَالِكَ عَنْ حَرَامِكَ، وَأَغْنِنِي بِفَضْلِكَ عَمَّنْ سِوَاكَ
Allahumma ikfini bi halalika 'an haramik, wa aghnini bi fadlika 'amman siwak.
Meaning: O Allah, suffice me with what is lawful against what is unlawful, and make me independent by Your bounty of all others besides You.
Source: Sunan al-Tirmidhi #3563Nabi (shallallahu alaihi wa sallam) used to seek refuge from debt, saying: 'O Allah, I seek refuge in You from worry and grief, from incapacity and laziness, from cowardice and miserliness, and from being overwhelmed by debt and overpowered by men' (Sahih al-Bukhari 6369). Debt was so serious in his view that he would initially not pray janazah for one who died with unpaid debts.
اللَّهُمَّ اكْفِنِي بِحَلَالِكَ عَنْ حَرَامِكَ، وَأَغْنِنِي بِفَضْلِكَ عَمَّنْ سِوَاكَ
A mukatab (contracted slave seeking freedom) came to Ali and said: 'I am unable to pay my contract.' Ali said: 'Shall I not teach you words that the Messenger of Allah (peace be upon him) taught me? If you had a debt as large as a mountain, Allah would pay it for you. Say: Allahumma ikfini bi halalika 'an haramik, wa aghnini bi fadlika 'amman siwak.'